Water vapor changing to liquid water

Venus is closer to the sun so it will be warmer than Earth. Mars is also further away from the sun than Earth so the temperature will differ and be colder.

Explanation:

A really long time ago Venus had water, but being closer to the Sun, most or all of this would have been in the form of vapour. Water vapour is a greenhouse gas, so heat from the Sun gets trapped and the temperature rises. This bakes carbon dioxide out of carbonate rocks, which increases the greenhouse effect and the temperature spirals up. Mars is only a tenth the mass of Earth and further away. So it struggles to hang onto a thick atmosphere and water is present only as ice. Without greenhouse gases the temperature falls and any carbon dioxide condenses as dry ice, cooling the planet still further.